The present invention relates essentially to the use of sulfites or metabisulfites in cosmetics, or for manufacturing a pharmaceutical composition, notably a dermatological composition, with melanogenesis-inhibiting effect or with depigmenting activity.
The invention also covers cosmetic compositions or pharmaceutical compositions, notably dermatological compositions thus obtained, with melanogenesis-inhibiting effect or with depigmenting activity.
The invention further covers a method of cosmetic depigmenting treatment which uses sulfites or metabisulfites as actives towards depigmentation.
It is known that in order to fight against sun's rays, the skin possesses different cells which are particularly adapted to this function: melanocytes.
During a complex process, melanogenesis, these cells produce a dark pigment, melanin, the effect of which is to protect the cutaneous structures and to increase the time needed for contracting sun-burn.
However, not every one of the melanins is protective, and there exists in particular a form of melanin, called phaeomelanin, which is extremely phototoxic. Capable as every melanin is of reacting with certain forms of free radicals, phaeomelanin causes the formation of free radicals which are even more toxic, which can cause irreversible damage to the genetic material of the keratinocytes.
On the other hand, certain disorders linked to a disfunctioning of the melanization unit can cause a hyper-pigmentation which is sometimes unaesthetic.
Thus, the use of inhibitors of melanin synthesis is particularly interesting in cosmetics, not only for applications wherein a real depigmentation is sought-after, as in the case of the blanching of highly pigmented skin or the inhibition of hyper-pigmentation in certain unaesthetic aspects for example, but also for applications aiming at lightening the tint, giving brightness to the skin, and a sparkle to the surface tissues.
This inhibition of the melanin synthesis may also be particularly interesting within the context of therapeutic treatment for treating a real pathology.
The invention does however aim at a simple cosmetic use although a pharmaceutical use within the context of pathology treatment is also envisaged and is also part of the invention.